Photographic-printing bath.



illbllli lll ll) SKATES PATENT (llt l llUEQ 'lllOMAS Mr NLY, OF LONDON, .ICNGLAYD.

Pt'lOTOGRl-lPHlC-PRlNTlNG BATH.

Specification of Letters Pate Patented April 23, 1907.

Application iiletl March 20,1906. Serial lie. 307,137,

and useful Improvements in Photographic 1 Printing .iaths, of winch the following is a specification.

The ObjOCt of my invention is to produce a .hoto 'ranhie n'inting bath bv ncans ofj a l r,

which pictures in insoluble colloids stch as gelatine or mucilaginous substances lira)? be obtained from photographic images consisting of metallie silver prodrced lr v development. Sueh pictures may l e prod-red upon the silver print itself in. pigmented colloid or by causing a pigmented gel line film to be acted upon by the silver print and then ransferring the gelatine lilm th .1s affected to another support. tollotvpe printing surfaces may also be produced by the same bath.

The method of carrying out m v invention is as followx l make up a solution, which I shall hereafter refer to as the pigmenting bath, consisting of: potassium or other alkali. biehromate about l; parts, potassium or other alkali iferricyanide about at parts, a soluble haloid salt such as pot assinm or other alkali bromide abo:.:t at parts, aluminium alum. about 2 parts, citric acid abort Obparts, Water to make 600 parts. I lind the addition of a small qrantitj, of alum and. citric results although it is not absolutely necessary.

instead of employing the bromide of potassiunr or other alkali i. may llttl'll'ltllf. emplo} one or more of the other solible haloid salts sreh as the chloride or iodide of )otassium or other alkali.

The bath is rsed in the following manner: I soak a piece of paper coated with pigmented gelatine others so called earbon tissue or pigment plaster m the above pigntenting bath until it lzecones saturated. in the meantime I place a bromide print or other ()l: course a rtulevelopeu silver print can be image consisting of metallie silver in a dish of cold water. As soon as the pigment plaster in the pigmenting bath has become limp or saturated l withdraw it from the acid to the other materials gives improved bath and place it face upwards u on a glass plate. I now take the bromide 1? int or other image eonsistmg ol' melaihe silver from the dish of water and place it carefully upon the pigment plaster lying upon thel glass plate and squeegee the two papers into contact. .l then place the combined papers 1 pen blotting paper r'ntil read) for develop- ;hent. l. lind this method of {hiring the carlon tiss'ic and cta ic silver iprint in contact to give good rest lts althoigh the} nia v le placed in contact l other nethods. lip

to this point the method of prodi'cing a pigmented pietiire upon the original silver print and an iirplession for transfer tpon another si'pport is the saute.

Alter the s pieegeed papers have been in contact about or minutes the image of the silver print will have acted upon the lilm of the pigmented gclntine and the two papers will require to be separated. There are two methods of separating these apers; according to the 'lirst method when the original silver print is intended to be the support of tli, picture, the adhering papers are soaked in hot wate and separated and the development takes place by n ashing away from the silver print all the pigmented gcla tine adhering thereto that has not been rendered insoluble by the action of the metallic silver. Aeeordilll' to the second method whenv it is desired to transfer the gelatine impression. to another support then the two adhering papers are plunged into eold water and separated by slowly and. hrmly pulling them.

asunder. lin. this case the pigmented gelatine lilm remains on. its support 'and holds an impression of the silver image and may be squeegced down upon a fresh support and developed b v removing the original support, washing away the soluble gelatine and leaving the picture on the fresh support. The black silver ol the print whieh will have become a faint brown in the operation may then be washed and redeveloped b any of the usual developers for bromide prints and again washed when it will serve for the production of another pigment print by being treated aeeording to the second method above described. in this manner several transfer prints can be obtained from one metallic silver print prodtu ed by development.

treated as deseribed H1 the lirst method and a pigmented picture produced upon the said redeveloped silver print.

Photographie egatives may be intensified and lantern slides may be colored by in .3115 of the hercinbefore described pigmen ting bath b v adopting the lirst method hereinbeifore deseribed .fmother applieation of my invention re- "with the suriace and allowed to remain in contact for about hali an hour, on stripping off he bromide silverprint, 'an impression of the bromide silver print in insoluble gelatine will remain on the surface of the collotype plate which is then washed. The collotype plate is then treated as usual to produce a collotype printing surface but as such treatment i'erms no part or the present invention it is not described. The impression is reversed as regards I get and lel't and therefore suitable for mecl'ianical printing.

lictures in a pigmented colloid such as gum can be produced by mixing a concentrated solution 0-: the above mentioned bath with a solution or pigmenteail gum which is spread on the metallic silver print with a brush or otherwise. After the silver print has acted on the pigmented colloid the soluble portions are washed away.

A combination or potassium rerricyamae and alkali bromide is well known as a bleach 1 tures was not known so far as I am aware prior to my invention thereof.

The results obtained by my invention are not due to any catalytic action but can be traced to chemical decomposition thus z- The H and K FeCy reduce the bichromate salt producing insolubility of the gela tine.

aving fully described my invention What I c aim and desire to secure by Letters Patent is 2 i 1. A bath for carrying out the herein described process, said bath, consisting of (l) a bi-chromate of an alkali, (2) a ferricyanide of an alkali (3) a soluble haloid salt of an alkali, (4) Water.

2. A bath or carrying out the herein described process, said bath consisting of (1) a bi-chroinate of an alkali, (2) a ferricyanide of an alkali (3) a soluble haloid salt of an alkali l) alum, (5) citric acid (6) Water.

In Witness whereof I have hereunto set my hand in presence of two witnesses.

THOMAS MANDY." Witnesses M. GIRLING, H. D. JAMESON. 

